The MFJ-401D EconoKeyer The MFJ-401D Econo Keyer II is a microprocessor controlled keyer that provides iambic key operation and dot-and-dash memory to make sending perfect code easier. It has tunable code speed, code weight, and sidetone frequency; it supports both direct and grid-block keying outputs. You also get to choose between Iambic Type "A" and Type "B" keying.